HELP FOR GARDENERS: DEALING WITH DREADED POISON IVY
I am seeing more and more of this growing in my grass than ever before. It is starting to concern me because I don’t know what it is. I have done ton of research and feel it is poison ivy. Unfortunately it is growing where the grass has been mowed. I wonder if you have any information on poison ivy you can share with me and if either you or anyone else is having the same problem. I am currently afraid to walk in my grass. Thank you. Sincerely: — Crystal from Bath
The first step in dealing with poison ivy (Toxicodendron radicans) is to identify it. Young poison ivy plants are often confused with several other common plants. I recommend the University of Maryland Extension site, Identifying Poison Ivy (https://extension.umd.edu/hgic/identifying-poisonivy) for guidance.
Identify poison ivy by its compound leaflet, three leaflike lobes. The middle leaflet is larger than the other two and has a longer stem. The other two have almost no stem and appear directly across from each other. The leaf veins alternate along the main leaf vein. Young leaves may be shiny. The leaf edges or margins can be toothed, lobed or almost smooth. The plants vine in the shade, but appear more like a bush in sunlight. These perennial plants climb trees and structures using aerial roots that make the stem of older plants appear hairy. The leaves turn yellow or a brilliant beautiful shade of red.
Poison ivy produces white berries that are a source of food for many songbirds during the fall and winter. All parts of the plant contain urushiol, the irritant that causes inflammation, blisters and rashes in many people.
Plants often confused with poison ivy include: Virginia creeper, Japanese honeysuckle, boxelder seedlings, Indian strawberry, brambles, Jack-in-thepulpit and clematis. So be sure what you have is poison ivy.
When dealing with poison ivy, make sure that all parts of your body are covered. There are treatments that cover the skin before exposure (i.e., Ivy Block) and others that wash off the oil after contact (i.e., Tecnu). Note that the oil will remain active on any clothes, shoes, tools, or pets that touch it. All of these should be washed or discarded to remove the oil.
One simple method of control is to cover your hand with a plastic bag and pull it over the plant as you remove it. Large vines on trees should be cut at the base and a portion of the stem removed to make sure it doesn’t regrow. The vines can be removed later, after they die off and dry out. The remaining root should be painted with herbicide. Multiple applications may be necessary to kill the root, so observe and treat any resprouting. In extreme cases, it may be necessary to treat smaller plants with an herbicide. In areas that contain other desirable plants, place a plastic bag over the plant and spray into the bag.
Disposal is also a problem, as the irritant remains active for several years. Do not burn poison ivy. It releases the irritant into the air and can cause extreme medical problems.
As far as composting, I would not recommend putting it into a home compost pile. The pulled plants can reroot in the pile, and the oils, even in dead plants, remain active in the compost for several years. When it comes to a commercial or municipal compost pile, the data are mixed. Some sources say that shredding the plants before composting will shorten the breakdown, but it also can coat the machines used with oil and create an oil-laden vapor during the shredding.
Obviously, the plant and the oils do break down over time. If not, we would be inundated with poison ivy. Some sources encourage burying the plants after they die. Others advocate disposing of the plants in plastic bags with the trash. I vote for trash disposal.
Japanese stilt grass follow-up Regarding Japanese stiltgrass — you say it should not be composted. Would it be OK to take it to a municipal mulch/ compost facility? They produce mulch/ compost at much hotter temperatures than a backyard pile; would that kill the seeds? I’ve never had any problems with mulch or compost from the Bethlehem
facility as far as importing weeds. My question could equally apply to poison ivy – I know that any part of the plant or root can cause a rash. Does the municipal composting process render it harmless? Thank you for your column – I enjoy it and have learned a lot. Keep up the good work! — Kathleen Konrad
As Kathleen notes, a commercial or municipal compost pile is generally much hotter than most backyard piles. These higher temperatures are generally sufficient to kill weed seeds. As far as poison ivy, as mentioned in the earlier response, the jury is still out. While it will break down eventually, the oils may survive the composting for a season or two.
Poison ivy can be identified by its three leaflike lobes. The middle leaflet is larger than the other two and has a longer stem. The other two have almost no stem and appear directly across from each other.